Detailed, mechanistic analysis of core debris melt progression behavior in LWR's
The MELPROG code is comprised of several explicitly linked modules that analyze different aspects of an accident. Water and vapor flows in the vessel are calculated in the FLUIDS module; this module also tracks the motion of solid and molten corium that forms when vessel structures melt or fail mechanically. At the beginning of an accident, the CORE module calculates heat transfer, oxidation, clad melting, dissolution and candling in the reactor core. If the fuel rods fragment, happened at Three-Mile Island, core melt progression is analyzed in the DEBRIS module; this module also treats debris beds that can form in the lower plenum during an accident. Detailed heat transfer and structural mechanics calculations are performed in the STRUCTURES module for the vessel walls, various support plates, the core baffle, the core barrel, core support columns and various support plates, the core baffle, the core barrel, core support columns and other structures in the vessel. Three-dimensional, dynamic view factors are calculated in the RADIATION module that provides boundary conditions for the CORE, DEBRIS and STRUCTURES modules. Additional MELPROG modules are being developed to analyze fuel-coolant interactions, fission product release and the ejection of debris from the reactor vessel into the containment building. This paper describes the MELPROG models that are operational during the late core melt progression phase of severe accidents. Brief descriptions of the FLUIDS, DEBRIS, STRUCTURES and RADIATION modules are provided in the following sections. Results from a demonstration calculation using a stand-alone version of the DEBRIS module are presented.
- Research Organization:
- Sandia National Labs., Albuquerque, NM (USA)
- DOE Contract Number:
- AC04-76DP00789
- OSTI ID:
- 7099124
- Report Number(s):
- SAND-88-0528C; CONF-881014-3; ON: DE88014521
- Resource Relation:
- Conference: International conference on thermal reactor safety, Avignon, France, 2 Oct 1988; Other Information: Portions of this document are illegible in microfiche products
- Country of Publication:
- United States
- Language:
- English
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